Science China Materials最新文献

The development of catalysts with highly efficient oxygen evolution performance and low-Ir loading is key to scaling up the application of proton exchange membrane (PEM) water electrolysis technology. Here, an Ir-skin catalyst (Ir@KM) is realized on a potassium-manganese oxide (K_0.25MnO_x (KM)) using an ion-exchange method. The Ir-skin over the prepared Ir@KM has a low Ir–Ir atomic distance, endowing an energetically favorable oxide path mechanism to allow a low theoretical overpotential of 0.13 V. Ir@KM offers a low overpotential of ∼280 mV at a current density of 10 mA cm⁻² and provides a high mass activity of up to 18,500 A at a cell voltage of 1.8 V in PEM, which is 17.6 times higher than that of IrO₂, demonstrating a significant advantage in reducing the cost of the membrane electrode. The presented Ir-skin concept represents a promising strategy to fabricate low-Ir catalyst with high activity and durability for practical applications of PEM.

Progressive skin fibrosis ultimately results in irreversible contractures, causing both joint dysfunction and cosmetic deformity. The key pathological features of skin fibrosis include persistent inflammation and abnormal accumulation of the extracellular matrix (ECM), with epithelialmesenchymal transition (EMT) playing a critical role in disease progression. However, current therapeutic strategies for cutaneous fibrosis are largely palliative and often require repeated interventions, with limited efficacy. Celastrol (Cel) exerts anti-inflammatory and anti-fibrotic effects in skin tissue, but its clinical application is limited by poor bioavailability and a narrow therapeutic window. Tetrahedral framework nucleic acid (tFNA), a novel nanocarrier system, exhibits multiple advantages, including enhanced cellular uptake, improved cell viability, and intrinsic anti-fibrotic and anti-inflammatory properties. Therefore, this study applied tFNA-Cel complex (TCC) as an advanced nanotherapeutic agent, designed to exert a synergistic anti-fibrotic effect. In this study, an in vitro model of skin fibrosis was established using human keratinocyte (HaCaT) cells treated with 5 ng mL⁻¹ transforming growth factor beta (TGF-β) for 24 h. The results showed that TCC significantly inhibited EMT progression by reducing α-smooth muscle actin (α-SMA) levels and increasing E-cadherin level. Compared to tFNA or Cel alone, TCC exhibited superior anti-fibrotic effects in the fibrosis model, as evidenced by modulation of SMAD family member 2 (SMAD2) signaling and collagen I expression. Furthermore, the TCC group showed lower levels of nuclear factor κB p65 (NF-κB p65), BCL-2-associated X protein (Bax), and reactive oxygen species (ROS) compared to the Cel or tFNA groups. These findings highlight TCC as a promising treatment for skin fibrosis, with its synergistic anti-fibrotic effects providing new therapeutic avenues.

NiMo-based catalysts show significant potential for the hydrogen evolution reaction (HER). Optimizing the electronic structure and enhancing mass transfer are two critical factors for improving catalytic performance, but they remain significant challenges. Herein, we present a route for synthesizing two-dimensional (2D) porous Mo₂N-Ni heterojunction nanosheets with tuned Ni-Mo ratio for enhanced alkaline HER performance. A precursor can be easily synthesized by assembling polyoxometalate clusters (PMo₁₂) with layered hydroxy oxides (Ni(OH)₂). It is found that the interaction between PMo₁₂ and Ni(OH)₂ can effectively protect the particles from significant agglomeration during pyrolysis, resulting in the formation of 2D porous sheets composed of small Mo₂N-Ni units. The transfer of electrons from Ni to Mo₂N results in the redistribution of electrons at the heterojunction, optimizing the adsorption and desorption of intermediates. Moreover, the 2D porous structure comprised of small particles enhances mass transfer, thereby reducing the impedance of the catalyst. Consequently, the catalyst with an optimized Mo/Ni ratio exhibits an overpotential of 19 mV at 10 mA cm⁻², being comparable to that of commercial Pt/C catalyst. The anion exchange membrane (AEM) electrolyzer, consisting of optimized Mo₂N-Ni and NiFe-LDH, achieves a current density of 500 mA cm⁻² at 1.80 V and can operate stably for 300 h. This assembly method offers an effective strategy for the large-scale preparation of efficient catalysts.

The integration of interfacial photothermal conversion and hydrovoltaic effect into bifunctional evaporators has emerged as a hopeful approach to address water and energy scarcities. However, developing low-cost bifunctional evaporators and elucidating the freshwater-electricity co-generation mechanism remain challenging. In this work, we prepare porous carbon from waste polyester through a metal-organic framework (MOF)-assisted carbonization strategy and subsequently fabricate a bifunctional evaporator for freshwater-hydroelectricity co-generation. The porous carbon contains rich oxygen-containing groups and shows hierarchical micro- and mesopores with a high specific surface area of 904 m² g⁻¹. The porous carbon-based evaporator shows broadband and high light absorption, localized thermal management, good hydrophilicity, and high flexibility. Benefiting from these merits, it achieves high-performance freshwater and hydroelectricity co-generation, with the open-circuit voltage of 250 mV, the short-circuit current of 14 µA, and the evaporation rate of 2.34 kg m⁻² h⁻¹. Hence, it is ranked among the most efficient freshwater-hydroelectricity co-generator. Additionally, the weakened hydrogen-bonding network reduces water evaporation enthalpy to 1.7 kJ g⁻¹. Mechanistic investigations reveal that selective Na⁺ interaction induces differential ion migration rate to generate streaming potential, as evidenced by molecular dynamics simulations. Meanwhile, the photothermal effect enhances voltage output by promoting interfacial ion concentration gradients. During the outdoor freshwater-electricity co-generation, it shows the voltage output of 250 mV and freshwater production of 2.34 kg m⁻². This work not only puts forward a new platform to fabricate advanced evaporators from low-cost waste plastics but also unravels the freshwater-electricity co-generation mechanism, offering scalable strategies to tackle freshwater and energy crises.

Two-dimensional MXene Ti₃C₂T_x demonstrates great promise in perovskite solar cells (PSCs). Herein, sulfur-terminated Ti₃C₂T_x (S-Ti₃C₂T_x) is developed by modifying Ti₃C₂T_x via a facile hydrothermal method using thioacetamide. As a perovskite additive, S-Ti₃C₂T_x outperforms pristine Ti₃C₂T_x by (1) significantly promoting grain growth, enhancing carrier mobility, and reducing defect density; (2) optimizing energy level alignment to lower interfacial energy barriers and minimize interface non-radiative recombination; (3) stabilizing uncoordinated Pb²⁺ and [PbI₆]⁴⁻ octahedra via Pb–S bonds while alleviating bulk lattice strain, as this Pb–S interaction exerts a “tape-like” effect. Based on this synergistic mechanism, PSCs with S-Ti₃C₂T_x achieve a champion efficiency of 25.51%—outperforming control (23.46%) and pristine Ti₃C₂T_x-based devices (24.54%)—with enhanced stability. This work highlights terminal group engineering as a critical strategy for advancing high-performance PSCs and their potential for emerging photovoltaic technologies.

Ruthenium-based materials (Ru and RuO₂) are promising electrocatalysts toward electrochemical water splitting (EWS) though there are still issues with them that needs to be resolved such as relatively strong adsorption strength of intermediates over Ru and oxidative dissolution of RuO₂. In this article, an overview of the recent progress and challenges with Ru-based electrocatalysts for EWS is provided. Firstly, fundamentals of EWS are summarized from the aspects of reaction mechanisms and activity descriptors. Next, the typical methods of fabricating Ru-based catalysts are demonstrated mainly including hydrothermal/solvothermal syntheses, organic ligand-assisted syntheses, pyrolysis, acid etching, cation exchange methods and molten salt-assisted syntheses. We then focus on illustrating the enhancing strategies toward creating advanced Ru-based electrocatalysts by demonstrating the typical examples, which include alloying, doping, structure design, interface engineering, single-atom catalyst design, high-entropy alloy design, phase engineering and defecting engineering. In this section, the structure-property correlation is elucidated aiming to the design of more efficient Ru-based electrocatalysts for EWS. Finally, we conclude the review by addressing the challenges and prospects of electrochemical water splitting and the development of Ru-based catalysts.

Intramolecular through-space charge-transfer (TSCT)-enabled thermally activated delayed fluorescence (TADF) emitters have shown exceptional potential for advancing organic light-emitting diode (OLED) technologies, owing to their efficient utilization of triplet excitons and optimized photophysical properties. To date, the intrinsic correlation among molecular geometries, intramolecular non-covalent interactions, and photophysical properties in TSCT-TADF emitters remains unconfirmed, and this study theoretically clarifies this critical correlation. Specifically, through integrating molecular engineering, screening strategies, first-principles calculations, energy decomposition analysis, and statistical modeling, we systematically investigated 24 experimentally reported TADF molecules, and 54 newly designed structures in both solution and thin-film environments. We establish a clear geometric criterion for high-efficiency TSCT-TADF emitters: donor-acceptor (D-A) dihedral angles below 25° and interfragment distances within 4 Å—conditions validated by both theoretical predictions and experimental evidence. Based on this insight, we designed two novel molecular libraries with benzene- or carbazole-derivative bridges, using O-bridged triphenylamine (DPXZ) as the donor and quinolino [3,2,1-de]acridine-5,9-dione (QAO) as the acceptor. Our calculations confirm that sub-25° D-A dihedral angles correlate with exceptional delayed fluorescence efficiency, with predictions reaching up to 96% and an average of 70% for the new thin film systems. This study provides a rational design strategy for high-performance TSCT-TADF emitters, significantly advancing the molecular-level understanding of through-space interactions and accelerating the discovery of tailored, efficient OLED materials.

Electrocatalytic co-reduction of CO₂ and nitrate offers an attractive and sustainable pathway for urea synthesis, as it enables the simultaneous valorization of nitrogenous waste and CO₂ into value-added chemicals. However, achieving ambient and high-performance urea electrosynthesis remains a persistent challenge, as it requires the simultaneous activation of CO₂ and efficient H₂O dissociation to supply active *H for *NO_x hydrogenation—ultimately forming key C-and N-containing intermediates necessary for effective C–N coupling. The stringent, sequential nature of the reaction requirements continues to present substantial challenges for the rational design of advanced multifunctional catalysts. Herein, we report a creative two-in-one catalyst, bifunctional Pd-single-atom-modified Cu (Pd₁Cu) nanorods, to synergistically promote the adsorption and stepwise activation of dual species, that is, CO₂ and H₂O, thereby effectively steering the reaction pathway toward the highly selective synthesis of urea. By integrating experimental evidence, in situ spectroscopy, and computational analyses, we clearly disclose that the atomically dispersed Pd sites kinetically favor the co-generation of *CO and *NH₂ (via H₂O dissociation-driven proton transfer), thereby forming an optimal intermediate balance that facilitates urea synthesis. More importantly, the rationally designed Pd₁Cu leverages dual metal active sites to enhance C–N coupling via combined electronic and geometric effects, substantially lowering the reaction energy barrier and improving selectivity toward urea.

Fabrication of large-area perovskite solar modules under ambient air conditions remains a critical challenge due to air sensitivity of perovskite intermediate phases during crystallization. Here, we introduce 2-iodoimidazole (IIZ) into the perovskite precursor, enabling the formation of an air-stable pure δ-phase intermediate, which, upon annealing, fully transforms into a highly oriented α-phase perovskite film with reduced defects and variability. Leveraging this approach, we achieve a stabilized power conversion efficiency of 20.9% for 927.5 cm² perovskite solar modules with high reproducibility. The encapsulated modules meet stringent international photovoltaic testing standards (IEC61215:2021), demonstrating excellent stability under continuous operation, thermal cycling (−40 to 85 °C) and damp heat (85 °C and 85% relative humidity).

The effective separation and utilization of photo-generated carriers are of great significance for promoting the development of photocatalysis, especially in the coupled process of photocatalytic H₂ production and value-added chemicals synthesis. To realize this goal, a sandwich-structured MnO₂@ZnIn₂S₄@Ti₃C₂ hollow sphere was designed and synthesized, in which MnO₂ and Ti₃C₂ were loaded on the inner and outer surfaces of ZnIn₂S₄, respectively. In the photocatalytic system, MnO₂ as oxidation cocatalyst and Ti₃C₂ as reduction cocatalyst can serve as photo-generated holes and electrons collectors, respectively, which boost the photo-generated carrier separation and create a spatially separated redox reaction. Furthermore, the unique hollow structure integrated into the photocatalytic system further endows a significant enhancement in light-harvesting ability. Remarkably, the optimal MnO₂@ZnIn₂S₄@Ti₃C₂ hollow sphere exhibits an outstanding the photocatalytic activity for coupled H₂ production (6.29 mmol g⁻¹ h⁻¹) and selective benzyl alcohol oxidation to benzaldehyde (5.26 mmol g⁻¹ h⁻¹), which is significantly superior to that of ZnIn₂S₄, MnO₂@ZnIn₂S₄, and ZnIn₂S₄@Ti₃C₂. By the in situ irradiated X-ray photoelectron spectroscopy, the result reveals that the spatially separated redox dual-cocatalysts can effectively impel the photo-generated carrier separation. Simultaneously, the intermediates during the benzyl alcohol oxidation process have also been confirmed through in situ electron paramagnetic resonance spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy. This work provides a reference and inspiration for constructing efficient photocatalysts that achieve an efficient coupling of photocatalytic H₂ production and value-added chemicals synthesis.